Python package for generating PNGs of code and math with custom highlighted regions using LaTeX.

Intended for use in creating presentations and tutorials, where you want the audience to attend to specific pieces of the code and/or associated math.

Ensure that the executables convert from ImageMagick and pdflatex are on the PATH.

Ensure that the highlighter.sty file provided in this repository is available to pdflatex.

Clone the repository, and install the Python package into your Python environment:

git clone [email protected]:probcomp/tutorial_highlighter.git
pip install tutorial_highlighter

There are two functions provided, render_code and render_math.

1. Create a string containing your code, with unique tags dispersed throughout (a string wrapped in (* and *)):

code = """\
@gen function model((*1*)floorplan(*2*), (*3*)approx_start_location(*4*), T)
    (*5*)start_location(*6*) ~ (*7*)mvnormal((*8*)approx_start_location(*9*), [0.004 0.0; 0.0 0.004])(*10*)
    (*11*)destination(*12*) ~ (*13*)uniform_destination_prior()(*14*)
    (*15*)trajectory(*16*) ~ (*17*)plan_path(*18*)(floorplan, start_location, destination)(*19*)
    precision = 50.0
    (*20*)measurements(*21*) ~ (*22*)measurement_and_motion_model(*23*)(trajectory, precision, T)(*24*)
end"""

2. Create a list of all tags in the code (to facilitate error-detection):

tags = [str(i) for i in range(1, 25)]

3. Indicate the set of regions (a pair of tags indicating the start and end) that should be highlighted. Regions may not overlap, and one tag cannot be used in the definition of more than one region. Both the start and end tags of a region must be on the same line. For example, to highlight the floorplan argument, we use:

regions = [("1", "2")]

NOTE: It is recommended to use more informative tags that are not simply numbers (as in this example), at the cost of being more verbose.

4. You provide listings settings and other LaTex prelude strings that should be included in the LaTeX file. The listings settings must be a tuple of two elements where the first element is a lstset block that defines an escapeinside option, and the second element is a tuple containing the two escapeinside strings, e.g.:

lstset = r"""
    \lstset{
      escapeinside={(@*}{*@)},
      basicstyle=\ttfamily\small,
      numbers=left
    }
"""
escapeinside = (r"(@*", r"*@)")
listings_settings = (lstset, escapeinside)

prelude = r"""
    % empty for now
"""

5. Then, render the code listing with highlighting to a PNG file:

import tutorial_highlighter

tutorial_highlighter.render_code(
    code, tags, regions, "code-1.png", listings_settings,
    varwidth_frac=1.05, user_prelude=prelude)

(You may need to adjust varwidth_frac to ensure your code is not cut off on the right).

You can generate many frames of a given code block, with different highlighting, e.g.:

1. Create a string containing your LaTeX math, with matched tags dispersed throughout (each tag is a string wrapped in (* and *)). Note that unlike for render_code, the same tag must be used twice, and each tag delineates a region that may be highlighted. (This distinction from render_code is due to implementation limitations, and it would be better to present a uniform tagging interface.)

math = r"""
\begin{equation*}\begin{array}{l}%
p(\mathbf{z}_{\mathrm{start}}, \mathbf{z}_{\mathrm{dest}},\mathbf{z}_{\mathrm{traj}}, \mathbf{x}_{\mathrm{meas}}) =\\
\begin{array}[t]{l}
(*1*)p(\mathbf{z}_{\mathrm{start}})(*1*)
\cdot (*2*)p(\mathbf{z}_{\mathrm{dest}})(*2*)
\cdot (*3*)p(\mathbf{z}_{\mathrm{traj}} | \mathbf{z}_{\mathrm{dest}}, \mathbf{z}_{\mathrm{start}})(*3*)\\
\cdot (*4*)p(\mathbf{x}_{\mathrm{meas}} | \mathbf{z}_{\mathrm{traj}})(*4*)
\end{array}
\end{array}
\end{equation*}
"""

2. Create a list of all tags in the code (to facilitate error-detection):

tags = [str(i) for i in range(1, 4+1)]

3. Indicate the set of regions (recall that each region is a single tag) to be highlighted. For example, to highlight only the expression of the density on the start variable, we use:

regions = ["1"]

NOTE: As above, it is recommended to use more informative tags that are not simply numbers (as in this example), at the cost of being more verbose.

4. As above, you may provide a prelude that will be added to the LaTeX file before the document begins:

prelude=r"""
\usepackage{amsmath,amssymb}
"""

5. Then, you render the math listing with highlighting to a PNG file:

import tutorial_highlighter

tutorial_highlighter.render_math(
    math, tags, regions, "math-1.png",
    varwidth_frac=0.55, user_prelude=prelude)